The present invention relates to a lockable filler cap assembly for fuel tanks and other fluid-holding containers.
Typically, an opening is made into the wall of such a tank. A substantially cylindrical sleeve is inserted into the opening and the sleeve is permanently attached to the tank to become a filler tube. The filler tube can be threaded on its inside surface which is mated with a filler cap having a complementary threaded portion on its outside surface. The threaded segments are typically cut as right hand threads, meaning the filler cap is removed by rotating the cap counterclockwise. Conversely, the filler cap is secured to the filler tube by engaging the complementary threaded portions of the cap and the filler tube and rotating the cap in a clockwise direction. In an alternative arrangement, the cap can be secured by a simple thread on the filler tube engaging lugs on the cap wherein only a quarter turn is required to effect the seal between the cap and the filler tube.
In numerous fluid handling and storage applications, it is desirable to seal the opening of a tank, such as the threaded conduit of a filler tube, with a closure which cannot be readily removed by unauthorized persons. Unauthorized access is desirable to prevent the theft of the contents of the tank as well as to prevent vandalism or sabotage by the addition of materials or foreign fluids to the contents of the tank. Locking caps for fuel tanks and similar containers are well known.
The present invention is an apparatus to provide a lockable cap assembly for fuel tanks and other fluid-holding vessels. The present invention is a lockable cap assembly providing an adaptable, interchangeable, easy to operate, and durable locking mechanism suitable for locking a cap onto the filler tubes of tanks carrying liquids such as motor fuels, water, wastewater, and sewage.
An object of the present invention is to provide an assembly that is readily adaptable to function as a normally operating non-locking filler cap and to function as a locked filler cap. The present invention includes a receptacle whereby an insert may be placed and locked into the receptacle. In the locked condition, a shield on the insert covers at least a portion of the cap, thereby discouraging access to the cap for its removal and, in turn, access to the contents of the associated tank.
Such an arrangement as described above is demonstrated in an example embodiment of the present invention wherein the cap has the profile of a marine deck fill plate. In typical usage, the marine deck fill plate is removed from its associated filler opening by engaging a pair of holes on the deck plate with a pair of complementary sized pins on a tool such as a wrench. Usually by turning the wrench and cap counterclockwise, the cap can be removed from its threaded engagement between an outside diameter of the cap and an inside diameter of the filler tube. Without the insert of the present invention placed into the receptacle of the cap, the cap is removable and replaceable in the same manner as any typical marine deck fill plate. To lock the cap of, the example embodiment to the filler tube of a boat or any other tank using a typical marine deck fill plate, an insert with a lock is placed into the receptacle of the cap. The insert includes a shield that at least covers the pair of holes on the deck plate profile of the cap. By locking the insert into the receptacle, removal of the cap is discouraged since the typical means of removal of the cap, i.e., the wrench or other similar tools as mentioned above, cannot be used since the shield of the insert covers and prevents usage of the pair of holes on the deck plate profile. In addition, the shield of the insert can be sized to completely cover the cap or to form a flushmount with the vicinity of the tank filler opening, thereby making an assembly that is resistant to prying or removal by pliers and other adaptable tools.
The locking of the insert into the cap of the present invention is provided by a lock being placed within a complementary opening inside the insert such that a latch operatively connected to the lock and placed in the locked position will protrude through a second opening to a position beyond the outside diameter of the insert and into an axially aligned groove in the receptacle of the cap. In this manner, the insert is secured within the receptacle of the cap of the present invention.
An object of the present invention is to provide an interchangeable assembly between the cap and the insert with the lock of the present invention. In this regard, the insert with the lock may be removed from a first cap and used in a second cap having the same sized receptacle for receipt of the insert with the lock. In this instance, the filler tubes associated with the first cap and the second cap, respectively, can always remain sealed with a normally functioning filler cap and access to a given tank is restricted only by the decided placement and usage of the locked insert. Such interchangeability can be useful in situations involving access to fuel tanks for rental vehicles and fleet vehicles, or for occasions requiring lockout and tagging procedures.
Another manner for securing the filler cap can be described in a second example embodiment of the present invention. As described earlier with regard to the operation of a marine deck plate, in this embodiment the shield of the insert may include a pair of holes as are found on the typical deck plate. In this example, the insert with the lock rotates freely within the cap when the cap is in the secure or “locked” setting. Since the shield on the insert spins freely within the cap, a wrench designed to engage a pair of holes on the deck plate with a pair of complementary sized pins would only act to spin the insert within the cap. However, when the insert is locked into the cap by engagement of a latch within a latch slot on the cap, the assembly comprised of the insert with lock and the cap will move as an entire unit. As a result, the assembly is removable and replaceable in the same manner as a typical marine deck fill plate.
An object of the present invention is to provide a locking filler assembly that can be readily adapted to pre-existing fillers on tanks. In addition the assembly can be made from any of a variety of materials such as metal, metal alloys, plastic, and reinforced plastic that are typically used to make a filler caps. The present invention is readily adaptable for use in corrosive environments such as in a marine application with exposure to salt water.
As is the state of the art, a mechanical seal between the filler tube and the cap can be obtained by close physical tolerances between the threaded portions of the filler tube and the cap. The seal may also be enabled or supplemented with sealing materials such as rubber, rubber compounds, rubber-containing mixtures, springs, deformable materials, and compressible materials.
In addition to the novel features and advantages mentioned above, other objects and advantages of the present invention will be readily apparent from the following descriptions of the drawings and preferred embodiments.